Chemical mechanical polishing pad having two types of sponge pores, method of making and use thereof
By creating a chemical mechanical polishing pad with two types of sponge pores in the polishing layer, the problems of insufficient polishing rate and surface flatness are solved, achieving more efficient polishing performance and simplified operation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- WANHUA CHEM GRP ELECTRONIC MATERIALS CO LTD
- Filing Date
- 2023-03-31
- Publication Date
- 2026-05-19
AI Technical Summary
Existing chemical mechanical polishing pads have shortcomings in polishing rate and surface flatness, and the operation method is relatively cumbersome, requiring further optimization.
A preparation method was used to form two types of sponge pores with different pore sizes in the polishing layer. The first type of sponge pores was formed by adding a temperature-sensitive hydrogel, and the second type of sponge pores were formed by curing in a non-solvent. Combining the two types of sponge pores improved the elastic recovery of the polishing pad and the flow rate of the polishing fluid.
It improves the surface flatness of polishing materials and the flow rate of polishing fluid, enhances polishing performance, and simplifies the operation process.
Smart Images
Figure CN118769125B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of chemical mechanical polishing technology, specifically to a chemical mechanical polishing pad with two types of sponge pores, its preparation method, and its application. Background Technology
[0002] Chemical mechanical polishing (CMP) combines the abrasive action of nanoscale particles with the chemical etching effect of a polishing slurry to planarize the surface of a workpiece on a polishing pad. CMP is widely used in the planarization process of semiconductor wafers and is an indispensable processing step in the production of wafers used to manufacture electronic components.
[0003] Chemical mechanical polishing (CMP) pads are key consumables in the CMP process, utilizing their unique porous structure to transport polishing fluid and remove reactants and debris generated during polishing. Among CMP pads, soft polyurethane microporous pads are typically used for finishing or final polishing to achieve a low defect rate in the polished material.
[0004] For soft polyurethane microporous polishing pads, adjustments are typically made to the pore structure of the polishing layer to improve polishing rates. For example, patent CN102029577A provides a polishing pad with a dual-pore structure, promoting high TEOS removal rates and high TEOS / Cu removal rate selectivity, as well as a low defect rate. This polishing pad uses a felt base, which slightly compromises on overall thickness uniformity. Patent CN113524026A provides an offset porous polishing pad, which has a combination of large, medium, and small pores in horizontally offset upper and lower sections to increase the pad's compression ratio and the contact area of the top polishing surface during polishing, thereby improving the polishing rate. However, implementing such a polishing pad is relatively cumbersome in terms of operation.
[0005] Therefore, further attempts and optimizations are still needed in the pore structure of the polishing layer to solve the problems existing in the current technology and improve the performance of the polishing pad. Summary of the Invention
[0006] To overcome the shortcomings of existing technologies, this invention provides a method for preparing a chemical mechanical polishing pad with two types of sponge pores. The polishing layer prepared by this method has two types of sponge pores with different pore sizes. The combination of these two types of sponge pores can, on the one hand, provide better elastic recovery of the polishing pad and improve the surface flatness of the polishing material, and on the other hand, accelerate the flow rate of the polishing liquid in the pores, thereby improving the polishing performance.
[0007] Another object of the present invention is to provide a chemical mechanical polishing pad having two types of sponge pores.
[0008] Another object of the present invention is to provide an application of this chemical mechanical polishing pad having two types of sponge pores.
[0009] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:
[0010] A method for preparing a chemical mechanical polishing pad with two types of sponge pores includes the following steps:
[0011] a) Dissolve polyurethane resin and additives in a solvent to prepare a coating slurry;
[0012] b) Apply the coating slurry evenly to the support layer at a certain thickness and dry it in an oven;
[0013] c) Then immediately immerse it in a coagulation bath to solidify and shape;
[0014] d) After washing and drying, the polishing layer is pressed with grooves and then bonded with a buffer layer, an adhesive backing layer and a release layer to obtain a chemical mechanical polishing pad.
[0015] In one specific implementation, the polyurethane resin in step a) is a solvent-based polyurethane resin. Preferably, the solvent-based polyurethane resin has a 100% modulus of 3 to 10 MPa, more preferably 5 to 8 MPa.
[0016] In one specific embodiment, the solvent is selected from any one of N,N-dimethylformamide, N,N-dimethylacetamide, or N-methylpyrrolidone, more preferably N,N-dimethylformamide.
[0017] In one specific embodiment, the additive in step a) includes a first additive and a second additive. Preferably, the first additive is a temperature-sensitive hydrogel, preferably a polymer hydrogel prepared with N-isopropylacrylamide as a monomer, and more preferably a poly-N-isopropylacrylamide hydrogel. The second additive is an auxiliary surfactant, preferably a nonionic surfactant. More preferably, the nonionic surfactant is selected from one or more of polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan palmitate monooleate, sorbitan tristearate, and sorbitan monooleate.
[0018] In one specific embodiment, the mass ratio of the polyurethane resin, the first additive, the second additive, and the solvent is 100:0.01-0.10:0.1-1.0:50-80, preferably 100:0.03-0.05:0.2-0.5:50-80.
[0019] In one specific implementation, the slurry coating thickness in step b) is 1.50–1.80 mm, preferably 1.60–1.75 mm.
[0020] In one specific implementation, the drying temperature in step b) is 40–80°C, preferably 50–70°C, and the drying time is 3–7 min, preferably 4–6 min.
[0021] In one specific embodiment, the coagulation bath in step c) is a mixture of N,N-dimethylformamide and water, wherein the mass ratio of N,N-dimethylformamide is 5% to 15%, preferably 7% to 10%.
[0022] In one specific implementation, the coagulation bath temperature in step c) is 20–50°C, preferably 25–35°C, and the curing time is 20–40 min, preferably 30–35 min.
[0023] In one specific implementation, the drying temperature in step d) is 80–150°C, preferably 100–120°C; the drying time is 10–50 min, preferably 20–40 min.
[0024] On the other hand, a chemical mechanical polishing pad prepared by the aforementioned method has a polishing layer in which there are two different pore sizes of sponge pores in the vertical cross-sectional direction.
[0025] On the other hand, a chemical mechanical polishing pad prepared by the aforementioned preparation method or the application of the aforementioned chemical mechanical polishing pad in chemical mechanical polishing.
[0026] Compared with existing technologies, the chemical mechanical polishing pads prepared by the method of this invention have the following beneficial effects:
[0027] 1) The preparation method of this invention is relatively simple. A specific void structure is formed in the polishing layer by heating the coating slurry on the support layer, followed by curing in a non-solvent environment to form a polishing layer with two different pore sizes in the vertical cross-section. For example, a polymer temperature-sensitive hydrogel prepared using N-isopropylacrylamide as a monomer is added to the slurry. Utilizing the shrinkage characteristic of this hydrogel at high temperatures, the first type of sponge pores is formed during the first drying step, followed by curing in the second non-solvent step to form the second type of sponge pores.
[0028] 2) The polishing layer of the chemical mechanical polishing pad prepared by the present invention has two types of sponge pores with different pore sizes. The combination of these two types of sponge pores can, on the one hand, provide better elastic recovery of the polishing pad and improve the surface flatness of the polishing material, and on the other hand, accelerate the flow rate of the polishing liquid in the pores, thereby improving the polishing performance. Attached Figure Description
[0029] Figure 1 The image shown is a scanning electron microscope (SEM) image of the chemical mechanical polishing pad prepared in Example 1 of this invention.
[0030] Figure 2 The image shows the scanning electron microscope (SEM) image of the chemical mechanical polishing pad prepared in Comparative Example 1 of this invention.
[0031] Wherein, 1 represents the first type of sponge pores that are uniformly distributed in the vertical cross-sectional direction of the polishing layer, and 2 represents the second type of sponge pores that are uniformly distributed in the vertical cross-sectional direction of the polishing layer. Detailed Implementation
[0032] To better understand the technical solution of the present invention, the following embodiments will further illustrate the method provided by the present invention. However, the present invention is not limited to the listed embodiments, but should also include any other known modifications within the scope of the claims of the present invention.
[0033] A method for preparing a chemical mechanical polishing pad with two types of sponge pores includes the following steps:
[0034] a) Dissolve polyurethane resin and additives in a solvent to prepare a coating slurry. Preferably, the solvent is selected from any one of N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone, more preferably N,N-dimethylformamide.
[0035] b) Apply the coating slurry evenly to the support layer at a certain thickness and then dry it slightly in the oven for a period of time;
[0036] c) Immediately immerse in a coagulation bath to solidify and shape;
[0037] d) After washing and drying, the polishing layer is pressed into grooves and then bonded with a buffer layer, an adhesive backing layer, and a release layer to obtain a polishing pad.
[0038] In step a), the polyurethane resin is a solvent-based polyurethane resin, preferably a wet-process polyurethane resin, which is a common synthetic leather resin. The solvent-based polyurethane resin has a 100% modulus of 3 to 10 MPa, for example, including but not limited to 3 MPa, 4 MPa, 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, and 10 MPa, preferably 5 to 8 MPa. Here, 100% modulus can also be referred to as 100% mold or 100% modulus, and all have the same meaning in this invention.
[0039] The first additive is a polymer hydrogel prepared with N-isopropylacrylamide as a monomer, and the amount of hydrogel added is 0.01-0.10% (based on the mass of polyurethane resin), such as 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.10%, etc., preferably 0.03-0.05%. The polymer hydrogel prepared with N-isopropylacrylamide as a monomer is, for example, a commercially available poly(N-isopropylacrylamide) hydrogel, and can also be chemically modified and altered based on this monomer, as long as it still has temperature-sensitive properties. The second additive is a nonionic surfactant. More preferably, the nonionic surfactant is selected from one or more of polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan palmitate monooleate, sorbitan tristearate, and sorbitan monooleate. The amount of nonionic surfactant added is 0.1-1.0% (based on the mass of polyurethane resin), such as 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.07%, 0.08%, 0.09%, 1.0%, etc., preferably 0.2-0.5%. The mass ratio of polyurethane resin, first additive, second additive, and solvent is 100:0.01-0.10:0.1-1.0:50-80, such as including but not limited to 100:0.01:0.1:50, 100:0.04:0.6:65, 100:0.10:1.0:80, etc.
[0040] In step b), the uniform coating can be achieved using existing technology; this invention has no limitations. For example, a coating machine can be used. The only limitation of this invention is controlling the coating thickness to be 1.50–1.80 mm, such as 1.50 mm, 1.55 mm, 1.60 mm, 1.65 mm, 1.70 mm, 1.75 mm, or 1.80 mm, but not limited to these values; preferably 1.60–1.75 mm. The drying temperature is 40–80°C, such as 40°C, 50°C, 60°C, 70°C, or 80°C, but not limited to these values; preferably 50–70°C. The drying time is 3–7 min, such as 3 min, 4 min, 5 min, 6 min, or 7 min, but not limited to these values; preferably 4–6 min. After drying, the coating is immediately transferred to a coagulation bath.
[0041] In step c), the coagulation bath is a mixture of N,N-dimethylformamide and water, wherein the mass percentage of N,N-dimethylformamide is 5% to 15%, for example 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, but not limited thereto, preferably 7% to 10%.
[0042] The coagulation bath temperature is 20–50°C, for example, 20°C, 30°C, 40°C, or 50°C, but not limited thereto, preferably 25–35°C; the curing time is 20–40 min, for example, 20 min, 25 min, 30 min, 35 min, or 40 min, but not limited thereto, preferably 30–35 min.
[0043] In step d), the drying temperature is 80-150℃, for example 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, but not limited thereto, preferably 100-120℃; the drying time is 10-50min, for example 10min, 20min, 30min, 40min, 50min, but not limited thereto, preferably 20-40min.
[0044] After the above drying steps, a polishing layer is obtained. The polishing layer is then combined with a buffer layer using conventional processes of existing technology. Adhesive backing is then applied, and a release layer is attached to obtain the chemical mechanical polishing pad with two types of sponge pores of the present invention.
[0045] The chemical mechanical polishing pad prepared by the method of the present invention can be applied in the field of chemical mechanical polishing, including but not limited to chemical mechanical polishing of silicon wafers, sapphire, etc.
[0046] The present invention will be further explained and illustrated below through more specific embodiments, but these do not constitute any limitation.
[0047] The main sources of raw materials used in the embodiments and comparative examples of this invention are shown in Table 1:
[0048] Table 1. Sources of main raw materials for examples and comparative examples
[0049]
[0050]
[0051] Unless otherwise specified, all other raw materials or reagents are obtained through commercially available channels.
[0052] Polished layer evaluation parameters:
[0053] ① Polishing layer thickness: The microstructure of the polishing layer cross section was observed using a VEGA TS5136XM scanning electron microscope, and the thickness of the polishing layer was measured using the scale of the scanning electron microscope's built-in software.
[0054] ② Hardness of polished layer: The hardness is determined by the depth that can be measured by pressing the indenter against the surface of the test piece with a spring using Shore A (test standard JIS K 6253).
[0055] ③ Polished layer compression ratio: Using a SCHOPPER type thickness gauge, with a pressure surface of 1cm, the thickness t0 was measured after applying an initial load of 3.74kPa for 30s, followed by the thickness t1 after applying a final pressure of 37.43kPa for 30s. Removing the total load, the compression ratio (%) = 100 × (t0 - t1) / t1
[0056] ④ Polishing test: Polishing test was conducted using an E460 CMP testing machine, ANJI AEP U3061A polishing fluid, polishing pad diameter 609mm, and copper target diameter 75mm.
[0057] The polishing parameters are as follows: polishing pressure 1.5psi, polishing speed 50-60rpm, polishing fluid flow rate 300mL / min, and polishing time 60s.
[0058] The film thickness was measured using an AMBioS XP-300 profilometer, and the average value of nine points was taken. The copper target removal rate was determined based on the difference before and after CMP. and non-uniformity % (NU%).
[0059] Example 1
[0060] Polishing layer preparation: 100 parts of solvent-based polyurethane resin ②, 0.03 parts of poly-N-isopropylacrylamide hydrogel, 0.2 parts of dehydrated sorbitan monooleate, and 50 parts of N,N-dimethylformamide were prepared into a polyurethane slurry. The slurry was coated onto a PET film with a thickness of 1.75 mm and dried in an oven at 60°C for 6 min. Then, it was immersed in a coagulation bath containing 7% N,N-dimethylformamide at 25°C for 35 min to cure. After washing with water, the PET film was separated and dried in an oven at 100°C for 30 min.
[0061] After the above drying steps, a polishing layer is obtained. Using existing steps, grooves are pressed into the polishing layer and combined with a buffer layer. Then, an adhesive backing is applied, and a release layer is attached to obtain a microporous polyurethane polishing pad.
[0062] The scanning electron microscope (SEM) image of the prepared polished layer is shown below. Figure 1 As shown, the polished layer has two types of sponge pores in the vertical height direction of the cross section: sponge pore 1 and sponge pore 2. The pore diameter of sponge pore 1 is 10-20 μm, and the pore diameter of sponge pore 2 is 3-5 μm.
[0063] Example 2
[0064] Polishing layer preparation: 100 parts of solvent-based polyurethane resin ③, 0.01 parts of poly-N-isopropylacrylamide hydrogel, 0.5 parts of dehydrated sorbitan tristearate, and 60 parts of N,N-dimethylformamide were prepared into a polyurethane slurry. The slurry was coated on a PET film with a thickness of 1.60 mm and dried in an oven at 50°C for 4 min. Then, it was immersed in a coagulation bath containing 10% N,N-dimethylformamide at 35°C for 30 min to cure. After washing with water, the PET film was separated and dried in an oven at 120°C for 20 min.
[0065] After the above drying steps, a polishing layer is obtained. Using existing steps, grooves are pressed into the polishing layer and combined with a buffer layer. Then, an adhesive backing is applied, and a release layer is attached to obtain a microporous polyurethane polishing pad.
[0066] Example 3
[0067] Polishing layer preparation: 100 parts of solvent-based polyurethane resin①, 0.05 parts of polyN-isopropylacrylamide hydrogel, 0.1 parts of polyoxyethylene sorbitan palmitate monoester, and 60 parts of N,N-dimethylformamide were prepared into a polyurethane slurry. The slurry was coated onto a PET film with a thickness of 1.80 mm and dried in an oven at 40°C for 7 min. Then, it was immersed in a coagulation bath containing 5% N,N-dimethylformamide at 50°C for 20 min to cure. After washing with water, the PET film was separated and dried in an oven at 80°C for 40 min.
[0068] After the above drying steps, a polishing layer is obtained. Using existing steps, grooves are pressed into the polishing layer and combined with a buffer layer. Then, an adhesive backing is applied, and a release layer is attached to obtain a microporous polyurethane polishing pad.
[0069] Example 4
[0070] Polishing layer preparation: 100 parts of solvent-based polyurethane resin ④, 0.10 parts of poly N-isopropylacrylamide hydrogel, 1.0 part of polyoxyethylene sorbitan monooleate, and 65 parts of N,N-dimethylformamide were prepared into a polyurethane slurry. The slurry was coated on a PET film with a thickness of 1.50 mm and dried in an oven at 70°C for 3 min. Then, it was immersed in a coagulation bath containing 7% N,N-dimethylformamide at 25°C for 40 min to cure. After washing with water, the PET film was separated and dried in an oven at 150°C for 10 min.
[0071] After the above drying steps, a polishing layer is obtained. Using existing steps, grooves are pressed into the polishing layer and combined with a buffer layer. Then, an adhesive backing is applied, and a release layer is attached to obtain a microporous polyurethane polishing pad.
[0072] Comparative Example 1
[0073] Polishing layer preparation: The polishing layer was prepared using the same steps as in Example 1, except that poly-N-isopropylacrylamide hydrogel was not added.
[0074] After the above drying steps, a polishing layer is obtained. Using existing steps, grooves are pressed into the polishing layer and combined with a buffer layer. Then, an adhesive backing is applied, and a release layer is attached to obtain a microporous polyurethane polishing pad.
[0075] The scanning electron microscope (SEM) image of the prepared polished layer is shown below. Figure 2 As shown, only one type of sponge pore 2 exists in this polished layer, with a pore size of 3-5 μm.
[0076] Comparative Example 2
[0077] Polishing layer preparation: The polishing layer was prepared using the same steps as in Example 2, except that the first drying temperature was 90°C.
[0078] After the above drying steps, a polishing layer is obtained. Using existing steps, grooves are pressed into the polishing layer and combined with a buffer layer. Then, an adhesive backing is applied, and a release layer is attached to obtain a microporous polyurethane polishing pad.
[0079] Comparative Example 3
[0080] Polishing layer preparation: The polishing layer was prepared using the same steps as in Example 3, except that the concentration of N,N-dimethylformamide in the coagulation bath was 20%.
[0081] After the above drying steps, a polishing layer is obtained. Using existing steps, grooves are pressed into the polishing layer and combined with a buffer layer. Then, an adhesive backing is applied, and a release layer is attached to obtain a microporous polyurethane polishing pad.
[0082] Comparative Example 4
[0083] Polishing layer preparation: The polishing layer was prepared using the same steps as in Example 4, except that solvent-based polyurethane resin ⑤ was used.
[0084] After the above drying steps, a polishing layer is obtained. Using existing steps, grooves are pressed into the polishing layer and combined with a buffer layer. Then, an adhesive backing is applied, and a release layer is attached to obtain a microporous polyurethane polishing pad.
[0085] The test results of the polished layer thickness, hardness, and compressibility prepared in the examples and comparative examples are shown in Table 2.
[0086] Table 2. Test results of polished layer thickness, hardness, and compressibility.
[0087]
[0088] The removal rate and non-uniformity of the polishing pads prepared in the examples and comparative examples were obtained by polishing tests. The test results are shown in Table 3.
[0089] Table 3. Results of Removal Rate and Non-uniformity Tests
[0090]
[0091] As shown in Table 3, the polishing pad prepared by the polishing layer of the present invention can improve the polishing rate and surface flatness of the polishing material.
[0092] Although the present invention has been described in detail through the preferred embodiments described above, it should be understood that the above description should not be considered as a limitation of the present invention. Those skilled in the art will understand that modifications or adjustments can be made to the present invention based on the teachings of this specification. These modifications or adjustments should also be within the scope defined by the claims of the present invention.
Claims
1. A method for preparing a chemical mechanical polishing pad with two types of sponge pores, characterized in that, Includes the following steps: a) Dissolve polyurethane resin and additives in a solvent to prepare a coating slurry; b) Apply the coating slurry evenly to the support layer at a certain thickness and dry it in an oven; c) Then immediately immerse it in a coagulation bath to solidify and shape; d) After washing and drying, the polishing layer is pressed with grooves and then bonded with a buffer layer, an adhesive backing layer and a release layer to obtain a chemical mechanical polishing pad; In step a), the polyurethane resin is a solvent-based polyurethane resin, and the 100% modulus of the solvent-based polyurethane resin is 3 to 10 MPa. The additives in step a) include a first additive and a second additive. The first additive is a temperature-sensitive hydrogel, which is a polymer hydrogel prepared with N-isopropylacrylamide as a monomer. In step c), the coagulation bath is a mixture of N,N-dimethylformamide and water, wherein the mass ratio of N,N-dimethylformamide is 5% to 15%.
2. The preparation method according to claim 1, characterized in that, The solvent-based polyurethane resin has a 100% modulus of 5-8 MPa.
3. The preparation method according to claim 1, characterized in that, The solvent mentioned in step a) is selected from any one of N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone.
4. The preparation method according to claim 3, characterized in that, The solvent mentioned in step a) is N,N-dimethylformamide.
5. The preparation method according to any one of claims 1-4, characterized in that, The first additive is poly(N-isopropylacrylamide) hydrogel; the second additive is an auxiliary surfactant.
6. The preparation method according to claim 5, characterized in that, The second additive is a nonionic surfactant.
7. The preparation method according to claim 6, characterized in that, The nonionic surfactant is selected from one or a mixture of polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan palmitate monooleate, sorbitan tristearate, and sorbitan monooleate.
8. The preparation method according to claim 1, characterized in that, The mass ratio of the polyurethane resin, the first additive, the second additive, and the solvent is 100:0.01~0.10:0.1~1.0:50~80.
9. The preparation method according to claim 8, characterized in that, The mass ratio of the polyurethane resin, the first additive, the second additive, and the solvent is 100:0.03~0.05:0.2~0.5:50~80.
10. The preparation method according to claim 1, characterized in that, In step b), the slurry coating thickness is 1.50–1.80 mm.
11. The preparation method according to claim 10, characterized in that, In step b), the slurry coating thickness is 1.60–1.75 mm.
12. The preparation method according to claim 1, 10, or 11, characterized in that, In step b), the drying temperature is 40–80°C and the drying time is 3–7 min.
13. The preparation method according to claim 12, characterized in that, In step b), the drying temperature is 50–70°C and the drying time is 4–6 min.
14. The preparation method according to claim 1, characterized in that, In step c), the mass ratio of N,N-dimethylformamide in the coagulation bath is 7% to 10%.
15. The preparation method according to claim 14, characterized in that, The coagulation bath temperature is 20–50℃, and the curing time is 20–40 min.
16. The preparation method according to claim 15, characterized in that, The coagulation bath temperature is 25-35℃, and the curing time is 30-35 minutes.
17. The preparation method according to claim 1, characterized in that, In step d), the drying temperature is 80–150°C and the drying time is 10–50 min.
18. The preparation method according to claim 17, characterized in that, In step d), the drying temperature is 100–120°C and the drying time is 20–40 min.
19. A chemical mechanical polishing pad prepared by the method according to any one of claims 1-18.
20. The use of the chemical mechanical polishing pad prepared by any one of claims 1-18 or the chemical mechanical polishing pad of claim 19 in chemical mechanical polishing.